Checking a chem. questions answer

[laker_gurl3]

the question is:

What is the pH of 1.50M of NH3?
the answer i got was a pH of 4.54..
is that correct?

 

[xanthym]

the question is:

What is the pH of 1.50M of NH3?
the answer i got was a pH of 4.54..
is that correct?

SOLUTION HINTS:
For aqueous ammonia solution:
NH₃ + H₂O ↔ NH₄⁺ + OH^-
K_b = 1.8×10^(-5) = [NH₄⁺][OH^-]/[NH₃]
::: ⇒ 1.8×10^(-5) = x²/(1.5 - x)
::: ⇒ x = [OH^-] = (5.18716×10^(-3))
::: ⇒ [H₃O⁺] = 10^(-14)/(5.18716×10^(-3))
::: ⇒ pH = 11.715


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[primarygun]

-log(H+)=pH
What's the pH value of 1M HCl?
I am afraid the answer is wrong as NH3 is an alkali